Optoelectronic retinal prosthesis: system design and performance

Area of Science:

• Biomedical Engineering
• Neuroscience
• Ophthalmology

Background:

• High-resolution retinal prostheses face challenges in electrode size, charge injection, stimulation precision, wireless signal delivery, and maintaining natural visual input.
• Existing systems require careful balancing of electrochemical safety, spatial resolution, and efficient data transmission.

Purpose of the Study:

• To discuss the engineering and biological challenges in designing high-resolution retinal prostheses.
• To present solutions for a photodiode array-based retinal implant system.

Main Methods:

• Utilizing a head-mounted near-to-eye projection system with near-infrared wavelengths to image processed video frames onto the retinal implant.
• Employing photodiodes to convert light into pulsed electric current, optimizing charge injection with a common biphasic bias waveform.
• Developing a system with scalable pixel sizes (25-100 microm) for 640-10,000 pixels on a 3 mm implant.

Main Results:

• The proposed system achieves stimulation at up to 50 Hz within a 10-degree central visual field.
• A full 30-degree visual field is accessible through eye movements.
• Pixel size scalability allows for high pixel density on a compact implant.

Conclusions:

• The photodiode array retinal prosthesis design effectively addresses critical challenges in visual restoration technology.
• The system offers a promising approach for high-resolution artificial vision with potential for natural visual field expansion.
• Further development could lead to significant advancements in treating blindness through retinal implants.